哪里漏了？

Question

我不明白！ Instruments 向我显示此方法中存在泄漏

-(void)loadData
{
    if (locationData != nil) {
        [locationData release];
    }

self.locationData = [[NSMutableArray alloc] init];

NSData *recievedData = [NSData dataWithContentsOfURL:[NSURL URLWithString:[NSString stringWithFormat:@"http://htmlwin001.******.net/blutalkasp/locations2.asp?uid=%@&von=%d&bis=%d", [[UIDevice currentDevice] uniqueIdentifier], von, bis]]];

NSString *recievedString = [[NSString alloc] initWithData:recievedData encoding:NSUTF8StringEncoding];

SBJsonParser *json = [[SBJsonParser alloc] init];
NSMutableDictionary *jsonData = [json objectWithString : recievedString];

NSString *tmpLocationData;
for (NSDictionary *location in [jsonData objectForKey:@"items"]) {
    Location *newLocation = [[Location alloc] init];
    tmpLocationData = [[NSString alloc]initWithFormat:@"%@", [location objectForKey:@"id"]];
    [newLocation setLocationID:tmpLocationData];
    [tmpLocationData release];
    tmpLocationData = [[NSString alloc]initWithFormat:@"%@", [[location objectForKey:@"locationname"] gtm_stringByUnescapingFromHTML]];
    [newLocation setLocationName:tmpLocationData];
    [tmpLocationData release];
    tmpLocationData = [[NSString alloc]initWithFormat:@"%@",[location objectForKey:@"locationdistance"]];
    [newLocation setLocationDistance:tmpLocationData];
    [tmpLocationData release];
    tmpLocationData = [[NSString alloc]initWithFormat:@"%@", [[location objectForKey:@"locationaddress"] gtm_stringByUnescapingFromHTML]];
    [newLocation setLocationAdress:tmpLocationData];
    [tmpLocationData release];
    tmpLocationData = [[NSString alloc]initWithFormat:@"%@", [[location objectForKey:@"locationdescription"] gtm_stringByUnescapingFromHTML]];
    [newLocation setLocationDescription:tmpLocationData];
    [tmpLocationData release];

    NSNumber *tmpLocationLat = [[NSNumber alloc] initWithInteger:[[location objectForKey:@"locationlatitude"]integerValue]];
    [newLocation setLocationPositionLat:tmpLocationLat];
    [tmpLocationLat release];

    NSNumber *tmpLocationLng = [[NSNumber alloc] initWithInteger:[[location objectForKey:@"locationlongitude"]integerValue]];
    [newLocation setLocationPositionLng:tmpLocationLng];
    [tmpLocationLng release];

    NSString *URL;
    URL = [location objectForKey:@"locationimage1"];
    URL = [URL stringByReplacingOccurrencesOfString:@"[SLASH]" withString:@"/"];
    NSString *tmpUrl1 = [[NSString alloc]initWithFormat:@"http://htmlwin001.******.net/blutalkasp/locationimages/data/%@", URL];
    [newLocation setLocationImageURL1:tmpUrl1];
    [tmpUrl1 release];

    URL = [location objectForKey:@"locationimage2"];
    URL = [URL stringByReplacingOccurrencesOfString:@"[SLASH]" withString:@"/"];
    NSString *tmpUrl2 = [[NSString alloc]initWithFormat:@"http://htmlwin001.******.net/blutalkasp/locationimages/data/%@", URL];
    [newLocation setLocationImageURL2:tmpUrl2];
    [tmpUrl2 release];

    URL = [location objectForKey:@"locationimage3"];
    URL = [URL stringByReplacingOccurrencesOfString:@"[SLASH]" withString:@"/"];
    NSString *tmpUrl3 = [[NSString alloc]initWithFormat:@"http://htmlwin001.******.net/blutalkasp/locationimages/data/%@", URL];
    [newLocation setLocationImageURL3:tmpUrl3]; //Leak geschlossen
    [tmpUrl3 release];

    [self.locationData addObject:newLocation];

    [newLocation release];
}   
[recievedString release];
[json release];

}

是否可能是 [nsdictionaryobject objectForKey:@"xy"]; 导致泄漏？

因为在乐器中，尤其是这些线条是有颜色的。正如你所看到的，我正在释放一切。 我对那个应用程序非常绝望。我什至开始通过 alloc/init/release 替换所有方便的构造函数（例如 initWithFormat 而不是 stringWithFormat）。特别是在循环中！

但有时甚至仪器也会崩溃！

Answer 1

if (locationData != nil) {
        [locationData release];
    }


self.locationData = [[NSMutableArray alloc] init];

这种模式是致命的；您直接释放一个实例变量，可能会留下一个悬空指针，然后通过 set 方法（通过点语法）分配一个值。

set方法会首先尝试释放locationData。

正如 Joe 指出的那样，它没有崩溃的唯一原因是您首先过度保留了 locationData。

在 -dealloc 之外，使用 self.locationData = nil; 来释放和清空实例变量。

Answer 2

如果属性 locationData 设置为保留，则您将在以下行中创建内存泄漏

//This is what is probably leaking
self.locationData = [[NSMutableArray alloc] init];
//Change that to
self.locationData = [[[NSMutableArray alloc] init] autorelease];

编辑：

这可能会给您带来以下行的新问题

//Remove this check to release locationData because the property will properly 
//handle memory management for you just by setting it
if (locationData != nil) {
    [locationData release];
}